Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 200545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 20 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
A 1009 MB LOW IS CENTERED NEAR 10N52W AND REMAINS EMBEDDED
WITHIN LOW-LEVEL CYCLONIC MONSOONAL FLOW ACROSS THE CENTRAL
TROPICAL ATLC. A TROPICAL WAVE TO THE EAST-NORTHEAST OF THE LOW
IS EXPECTED TO INJECT ENERGY INTO THE LOW DURING THE NEXT 24 TO
48 HOURS WITH MOST GLOBAL MODELS SUGGESTING DEVELOPMENT OF THE
SURFACE LOW THAT TRACKS W-NW TOWARD THE LEEWARD ISLANDS AND NE
CARIBBEAN BY FRIDAY. ISOLATED MODERATE CONVECTION IS FROM 06N-
13N BETWEEN 50W-56W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 11N18W TO 21N18W MOVING W AT 10-15
KT. THE WAVE HAS EMERGED OFF THE WEST AFRICAN COAST DURING THE
PAST 6 HOURS AND COINCIDES WITH AN AMPLIFIED 700 MB TROUGH
BETWEEN 16W-23W AND 850 MB RELATIVE VORTICITY FOCUSED IN THE
VICINITY OF 14N20W WITHIN THE MONSOON TROUGH AXIS AND NEAR
21N19W AT THE NORTHERN EXTENT OF THE WAVE AXIS. ISOLATED
MODERATE CONVECTION IS FROM 15N-17N BETWEEN 17W-20W.

TROPICAL WAVE EXTENDS FROM 13N43W TO 21N48W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH 700 MB TROUGHING ALOFT AND A MAXIMUM IN
850 MB RELATIVE VORTICITY NOTED ALONG THE MONSOON TROUGH AXIS
NEAR 14N43W. NO SIGNIFICANT CONVECTION IS OCCURRING WITH THE
WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 11N56W TO 20N57W MOVING W AT 20 KT.
700 MB TROUGHING ASSOCIATED WITH THE WAVE HAS LIKELY MERGED WITH
MID-LATITUDE 700 MB TROUGHING OVER THE CENTRAL ATLC...HOWEVER
RESIDUAL ENERGY CONTINUES TO MOVE WEST OF THE 1009 MB SPECIAL
FEATURES LOW EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10N52W. NO
SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 08N93W TO 21N91W MOVING W AT 20-25
KT. MOST OF THE ENERGY ASSOCIATED WITH THIS WAVE LIES IN THE
EAST PACIFIC REGION...HOWEVER 850 MB RELATIVE VORTICITY FIELDS
REMAIN MAXIMIZED ACROSS PORTIONS OF SOUTHERN MEXICO THAT
CONTINUE TO SUPPORT ISOLATED MODERATE CONVECTION FROM 16N-21N
BETWEEN 94W-98W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N20W TO
13N42W TO A 1009 MB LOW PRES NEAR 10N52W TO 09N61W. ISOLATED
MODERATE CONVECTION IS FROM 12N-14N BETWEEN 25W-28W...AND FROM
10N-13N BETWEEN 44W-49W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW IS CENTERED NEAR 23N97W THAT INFLUENCES MUCH
OF THE WESTERN GULF W OF 90W WITH MOIST SOUTH-SOUTHWESTERLY FLOW
ALOFT. WHILE SURFACE RIDGING EXTENDS ALONG 28N ACROSS THE
BASIN...DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW IS
ADVECTING MOISTURE NORTHWARD AND GENERATING ISOLATED SHOWERS AND
TSTMS ACROSS INLAND PORTIONS OF EASTERN MEXICO S OF 22N AND
ACROSS THE GULF WATERS FROM 22N-27N BETWEEN 89W-95W.
ELSEWHERE...THE SURFACE RIDGE EXTENDING FROM THE SW NORTH ATLC
IS PROVIDING FOR OVERALL FAIR CONDITIONS AND MOSTLY CLEAR SKIES
ACROSS THE EASTERN GULF THIS EVENING. A FEW ISOLATED SHOWERS AND
TSTMS ARE NOTED E OF 90W AS SOUTHWESTERLY FLOW ALOFT INFLUENCES
THE GULF ON THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE
CENTERED OVER THE SOUTHERN FLORIDA PENINSULA NEAR 26N81W. THE
SURFACE RIDGE IS EXPECTED TO REMAIN ANCHORED ALONG 28N/29N
THROUGH SUNDAY WITH GENTLE TO MODERATE EAST WINDS.

CARIBBEAN SEA...
A MAJORITY OF THE CARIBBEAN IS UNDER THE INFLUENCE OF DRY UPPER
LEVEL CYCLONIC CIRCULATIONS ALOFT...ONE CENTERED OVER THE NW
CARIBBEAN NEAR 18N82W AND THE OTHER CENTERED NEAR 21N63W THAT
EXTENDS UPPER LEVEL TROUGHING OVER MUCH OF THE EASTERN CARIBBEAN
E OF 73W. WATER VAPOR IMAGERY CONFIRMS THE DRY AIR ALOFT AND
THIS IS PROVIDING FOR OVERALL STABLE CONDITIONS THIS
EVENING...HOWEVER ISOLATED SHOWERS ARE NOTED IN THE VICINITY OF
18N85W...AND ACROSS THE NE CARIBBEAN N OF 16N BETWEEN 61W-70W.
THE AREA OF LOW-LEVEL MOISTURE ACROSS THE NE CARIBBEAN HAS
CONTINUED TO MOVE SOUTHWESTWARD DURING THE PAST 24 HOURS AS A
TROPICAL WAVE APPROACHES FROM THE EAST. OTHERWISE...SCATTERED
SHOWERS AND TSTMS ARE OCCURRING ACROSS THE SW CARIBBEAN IN AN
AREA OF MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE AND WITHIN CLOSE
PROXIMITY TO THE MONSOON TROUGH AXIS SOUTH OF PANAMA IN THE EAST
PACIFIC. MODERATE TO FRESH TRADES ARE EXPECTED TO PERSIST
GENERALLY S OF 17N BETWEEN 68W-80W.

...HISPANIOLA...
CURRENTLY...ISOLATED SHOWER ACTIVITY CONTINUES ACROSS THE ISLAND
WITH LOW-LEVEL MOISTURE COVERING A LARGE AREA TO THE EAST ACROSS
THE NE CARIBBEAN SEA AND PORTIONS OF THE SW NORTH ATLC FROM 16N-
21N BETWEEN 61W-72W. THE APPROACH OF A WEAK TROPICAL WAVE WILL
ALSO IMPACT THE ISLAND DURING THE NEXT 24 TO 48 HOURS WITH THE
USUAL POSSIBILITY OF AFTERNOON AND EVENING CONVECTION DUE TO
PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE IS ANCHORED OVER THE SW NORTH ATLC
NEAR 26N81W THAT EXTENDS AN AXIS NE TO 30N70W SUPPORTING SURFACE
RIDGING ACROSS MUCH OF THE SW NORTH ATLC W OF 60W. TO THE NORTH
OF THE SURFACE RIDGE AXIS ALONG 27N/28N...LOWER PRESSURE OFF THE
COAST OF THE DELMARVA EXTENDS WEAK SURFACE TROUGHING ALONG THE
EASTERN SEABOARD TO 30N WITH ISOLATED SHOWERS AND TSTMS
OCCURRING IN THE VICINITY OF 31N79W. OTHERWISE...THE REMAINDER
OF THE SW NORTH ATLC REMAINS UNDER MOSTLY FAIR SKIES AND
CONDITIONS THIS EVENING. FARTHER EAST...THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC ARE ALSO UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED SW OF THE
AZORES NEAR 35N33W. A DISSIPATING STATIONARY FRONT EXTENDS FROM
34N20W TO 31N28W ON THE SOUTHEASTERN PERIPHERY OF THE
RIDGE...HOWEVER IS NOT PRODUCING ANY SENSIBLE WEATHER AT THIS
TIME.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN



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